1. Field of the Invention
This invention relates generally to phonograph equipment and more particularly to a fluidically driven turntable for rotatably supporting phonograph records, memory disks or the like.
2. Description of the Prior Art
Conventional turntables are normally supported on a base via a spring-mounting arrangement. The use of such a spring-mounting arrangements serves to protect the turntable from shocks and vibrations external to the instrument, but makes no correction for internal mechanical vibrations and rumble and provides no means compensating for variations in drive speed.
U.S. Pat. Nos. 3,103,364 and 3,674,278 teach phonograph turntables wherein the turntable is supported on a film of air to help isolate the turntable from vibration and mechanical noise. The use of an air bearing provides only a very limited type of vibration isolation and provides no means for compensating for variations in drive speed.
U.S. Pat. Nos. 1,747,866; 1,817,758, and 2,113,390 teach prior art phonograph apparatus wherein the turntable employs some type of flywheel arrangement to compensate for fluctuations in drive speed. Friction is reduced and/or damping action is achieved by the use of a viscuous medium such as oil which may also serve a lubricating function.
None of these patents teach a true fluid coupling whereby the turntable is isolated from the drive means so as to eliminate or at least substantially reduce the undesireable effects resulting from mechanical vibrations produced in the bearings and the like. Furthermore, none of these patents teach accomplishing the flywheel effect to compensate for drive speed fluctuations by driveably rotating or circulating a quantity of liquid within a tank such that the liquid, itself drives the actual turntable and forms a flywheel therewith.
Many of the approaches taught by the prior art involve a deterioration of performance as the parts wear. Most of the prior art systems cannot insure that the turntable is driven with an absolutely constant speed due to motor wear, deterioration of the motor bearings, variations in line voltage, and the like. The mechanical coupling means and springs used to isolate the turntable from vibration and shock meet with only limited success and none is truely capable of isolating the turntable from internal vibration, oscillation and rumble generated within the unit itself.
The present invention provides a fluidically driven turntable which overcomes the disadvantages of the prior art and permits a vastly more accurate and faithful reproduction of the sounds or information recorded.